Our major goals for the current year include (1) increasing the reliability of our micro calcium and phosphate determinations so that they can be used to analyze the solutions contained in micro wells drilled into enamel sections, and (2) applying these techniques to study artificial lesions which closely resemble those found in vivo. New projects we are initiating include (1) a series of measurements on the changes in the pH of solutions within preexisting lesions as functions of the composition and pH of the surrounding fluid, (2) measurements on solutions within lesions that are subjected to various remineralizing solutions, and (3) the development and testing of some simple methods for measuring fluoride content of enamel in vitro. The overall goals of this research include the following: generation of data that will provide a basic means for testing mechanisms of dental decay; development of easily applicable microanalytical techniques for dental research; and development of a laboratory model for testing the efficacy of caries-prevention and tooth-remineralization techniques.